Perhaps you should try some spelling variations:
dau truc » dai truc, doan truc, dau tu
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
nang xa » lang xa, nang ma, mang xa
hieu va » lieu va, hieu qua
va hanh » van hanh, va thanh, va danh
tu tren » tu truyen, tu tieng, tu trong
vi tu » vi tut, voi tu, va tu

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach ky ((nang xa) or (nang x)) hoi. hieu va ((dau truc) OR (cau truc)) va hanh vi tu tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky ((nang xa) OR (nang x)) hoi. hieu va ((dau truc) OR (cau truc)) va hanh vi tu tren.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky ((nang xa) or (nang x)) hoi. hieu va ((dau truc) OR (cau truc)) va hanh vi tu tren".
• Adding a wildcard symbol may retrieve word variants: tu sach ky ((nang xa) or (nang x)) hoi. hieu va ((dau truc) OR (cau truc)) va hanh vi tu tren*.